Topics · Primary Maths · Time & Calendar
Time: the measure that is not base ten
Sixty seconds in a minute, sixty minutes in an hour, twenty-four hours in a day. Nothing about time carries at ten, and almost every mistake on this topic is a sum done as though it did.
- 346 exam papers analysed
- appears in 74% of P6 Maths papers
- ~3 min read
01 Reading the hands
The long hand shows minutes and goes all the way round in an hour. The short hand shows hours and takes twelve hours to do the same trip.
So the hour hand is almost never pointing straight at a number. At half past three it sits between the 3 and the 4, because half an hour of the journey from 3 to 4 is done. Reading it as pointing at the 4 gives half past four — an hour wrong.
02 24-hour time
The 24-hour clock always uses four digits and never am or pm: 09 05 is five past nine in the morning, 21 05 is five past nine at night.
Afternoon and evening: add 12 to the hour. 3 pm is 15 00. Going back: subtract 12 from anything past 12 00.
Midnight is 00 00 and noon is 12 00. Those two are the ones worth memorising, because they are the ones that get swapped.
03 Duration: count on, do not subtract
Working out how long something lasted by subtracting the two times in columns is where the topic goes wrong, because minutes carry at 60 and the column method assumes 10.
Count on instead, in easy jumps: to the next whole hour, then whole hours, then the last minutes.
From 09 45 to 13 20: 15 minutes to 10 00, then 3 hours to 13 00, then 20 minutes — total 3 hours 35 minutes.
04 The calendar
Thirty days have September, April, June and November. All the rest have 31, except February, which has 28 — or 29 in a leap year.
A leap year is usually every fourth year: 2024, 2028. Papers give you the year, so check whether it divides by 4.
Counting days across months means counting the real length of each month, not assuming 30.
05 How to say them
These are words most children have never said out loud, and a word you cannot say is a word you avoid using. Capitals mark the syllable you lean on. Tap the speaker to hear it.
- durationsaydyoo-RAY-shuhnmore than onedurations
How long something lasts, from its start to its end.
- amsayay EM
Before noon. 7 am is seven in the morning.
- pmsaypee EM
After noon. 7 pm is seven in the evening, which is 19 00.
- 24-hour clock
Times written with four digits from 00 00 to 23 59, with no am or pm.
- leap yearmore than oneleap years
A year with 29 days in February, usually every fourth year.
06 What each level is tested on
The same topic, asked differently as it goes up. The percentage is the share of papers at that level in which it appears.
- P2
Telling the time to five minutes, and the days of the week.
Practise P2 Time & Calendar — 10 questions →55% of P2 papers
- P3
Reading and writing 24-hour time, and finding simple durations.
Practise P3 Time & Calendar — 10 questions →50% of P3 papers
- P4
Durations across the hour and across midday, and calendar problems.
Practise P4 Time & Calendar — 10 questions →58% of P4 papers
- P5
Timetables, and time inside word problems.
Practise P5 Time & Calendar — 10 questions →36% of P5 papers
- P6
Time in rate and speed problems, and multi-step schedules.
Practise P6 Time & Calendar — 10 questions →74% of P6 papers
07 Mistakes worth knowing about
Each of these is wrong. Decide why before you open it.
“Half past three — the small hand is nearly at 4, so it is half past four.”
The hour hand moves gradually. Between the 3 and the 4 means the hour is still 3.
“From 09 45 to 13 20 is 13 20 − 09 45 = 3 hours 85 minutes.”
Minutes carry at 60, not 100. Count on instead: 15 min + 3 h + 20 min = 3 h 35 min.
“3 pm is 13 00.”
Add 12 to the hour: 3 + 12 = 15, so 15 00. 13 00 is 1 pm.
“1.5 hours is 1 hour 50 minutes.”
1 hour 30 minutes. Half an hour is 30 minutes, because an hour is 60.
“Every month has 30 days for counting purposes.”
Only four do. Counting across a 31-day month or February gets a different answer.
Now try it
50 questions across 5 levels, marked as you go with the working shown.